var scrollMoveObj = null,

scrollPageY = 0,

scrollY = 0;

var scrollDivList = new Array();

    // obj需要添加滚动条的对象 w滚动条宽度 className滚动条样式名称

    // obj元素 必须指定高度，并设置overflow:hidden;

    // 如要兼容IE6 必须给obj元素 指定 overflow:hidden;

     var lpTab = document.getElementById("lp-map-tab");

    // var obj2 = $('.lpm-footer-4').get(0);

     jsScroll(lpTab, 5, 'divScrollBar');

    // jsScroll(obj2,5, 'divScrollBar');

        

     

    function jsScroll(obj, w, className) {

        if (typeof(obj) == 'string') {

            obj = document.getElementById(obj);

        }

        //当内容未超出现在高度时，不添加滚动条    

        if (!obj || obj.scrollHeight <= obj.clientHeight || obj.clientHeight == 0) {

            return;

        }  

        obj.scrollBarWidth = w || 6;

        obj.style.overflow = 'hidden';

        obj.scrollBar = document.createElement('div');

        document.body.appendChild(obj.scrollBar);

        obj.scrollBarIndex = document.createElement('div');

        obj.scrollBar.appendChild(obj.scrollBarIndex);

        obj.scrollBar.style.position = 'absolute';

        obj.scrollBarIndex.style.position = 'absolute';

        obj.scrollBar.className = className || '';

        if (!className) {

            obj.scrollBar.style.backgroundColor = '#ddd';

            obj.scrollBarIndex.style.backgroundColor = '#aaa';

        }



        scrollDivList.push(obj);

        scrollResetSize(obj);



        //使用鼠标滚轮滚动

        obj.scrollBar.scrollDiv = obj;

        obj.scrollBarIndex.scrollDiv = obj;

        obj.onmousewheel = scrollMove;

        obj.scrollBar.onmousewheel = scrollMove;

        obj.scrollBarIndex.onmousewheel = scrollMove;

        if (obj.addEventListener) {

            obj.addEventListener('DOMMouseScroll', scrollMove, false);

        }



        //拖动滚动条滚动

        obj.scrollBarIndex.onmousedown = function(evt) {

            evt = evt || event;

            scrollPageY = evt.clientY;

            scrollY = this.scrollDiv.scrollTop;

            isScrollMove = true;

            document.body.onselectstart = function() {

                return false

            };

            scrollMoveObj = this.scrollDiv;

            if (this.scrollDiv.scrollBar.className == '') {

                this.scrollDiv.scrollBarIndex.style.backgroundColor = '#888';

            }

            return false;

        }

    }



    //当页面大小发生变化时，重新计算滚动条位置

    window.onresize = function() {

        for (var i = 0; i < scrollDivList.length; i++) {

            scrollResetSize(scrollDivList[i]);

        }

    }



    //计算滚动条位置



    function scrollResetSize(o) {

        if (o.scrollHeight <= o.clientHeight) {

            o.scrollTop = 0;

            o.scrollBar.style.display = 'none';

        } else {

            o.scrollBar.style.display = 'block';

        }

        var x = 0,

            y = 0;

        var p = o;

        while (p) {

            x += p.offsetLeft;

            y += p.offsetTop;

            p = p.offsetParent;

        }

        var borderTop = parseInt(o.style.borderTopWidth || 0);

        var borderBottom = parseInt(o.style.borderBottomWidth || 0);

        o.scrollBar.style.width = o.scrollBarWidth + 'px';

        o.scrollBar.style.height = o.clientHeight + 'px';

        o.scrollBar.style.top = y + borderTop + 'px';

        o.scrollBar.style.left = x + o.offsetWidth - o.scrollBarWidth + 'px';

        o.scrollBarIndex.style.width = o.scrollBarWidth + 'px';

        var h = o.clientHeight - (o.scrollHeight - o.clientHeight);

        //当滚动条滑块最小20个像素

        if (h < 20) {

            h = 20;

        }

        o.scrollBarHeight = h;

        o.scrollBarIndex.style.height = h + 'px';

        o.scrollBarIndex.style.left = '0px';

        setScrollPosition(o);

    }



    function setScrollPosition(o) {

        o.scrollBarIndex.style.top = (o.clientHeight - o.scrollBarHeight) * o.scrollTop / (o.scrollHeight - o.clientHeight) + 'px';

    }



    document.documentElement.onmousemove = function(evt) {

        if (!scrollMoveObj) return;

        evt = evt || event;

        var per = (scrollMoveObj.scrollHeight - scrollMoveObj.clientHeight) / (scrollMoveObj.clientHeight - scrollMoveObj.scrollBarHeight)

        scrollMoveObj.scrollTop = scrollY - (scrollPageY - evt.clientY) * per;

        setScrollPosition(scrollMoveObj);

    }

    document.documentElement.onmouseup = function(evt) {

        if (!scrollMoveObj) return;

        if (scrollMoveObj.scrollBar.className == '') {

            scrollMoveObj.scrollBarIndex.style.backgroundColor = '#aaa';

        }

        scrollMoveObj = null;

        document.body.onselectstart = function() {

            return true

        };

    }



    // 鼠标滚轮滚动



    function scrollMove(evt) {

        var div = this.scrollDiv || this;

        if (div.scrollHeight <= div.clientHeight) return true;

        evt = evt || event;

        var b = true;

        if (evt.wheelDelta) {

            b = evt.wheelDelta > 0 ? false : true;

        } else {

            b = evt.detail < 0 ? false : true;

        }

        var step = 20;

        if (b) {

            if (div.scrollTop >= (div.scrollHeight - div.clientHeight)) return true;

            div.scrollTop += step;

        } else {

            if (div.scrollTop == 0) return true;

            div.scrollTop -= step;

        }

        setScrollPosition(div);



        if (evt.preventDefault) {

            evt.preventDefault();

        }

        return false;

    }